Worldwide concern over the quality of the environment and the need to recycle what was once considered waste is ever-growing. Paper and other cellulose fiber products, such as cardboard, are recyclable and measures exist which remove inks and water-soluble adhesives.
One of the problems with paper and related products is that they also often contain labels having a pressure-sensitive adhesive which have proven difficult to separate from paper fibers under normal pulping conditions. This is because the adhesive tends to agglomerate or stay intact and remain with the paper fibers.
Attention has, in the past, been focused on adhesives for splicing tape used to couple one roll of paper to another. The art has developed very specific water soluble pressure-sensitive adhesives characterized as water dispersible and which, when used, will pass TAPPI Useful Method 213--"Repulpability of Splice Adhesive Compositions" incorporated herein by reference. Such water dispersible adhesives and tapes are described for instance in U.S. Pat. No. 3,441,430 to Peterson; U.S. Pat. No. 3,865,770 to Blake; U.S. Pat. No. 4,052,368 to Larson; U.S. Pat. No. 4,413,080 to Blake; and U.S. Pat. No. 4,569,960 also to Blake, each incorporated herein by reference. The problem with repulpable pressure-sensitive adhesives used in the splicing tapes which are the subject matter of such patents, is that extreme precautions have to be followed in storage and handling of the splicing tapes. The adhesives, for instance, have to be maintained at a controlled constant relative humidity in moisture resistant containers. Otherwise, the adhesive will quickly dry out and lose its tack. While such adhesives are acceptable for the controlled environment of paper manufacture, they are totally unacceptable for general purpose adhesive applications, such as labels which may be applied to cardboard boxes or informational labels applied to correspondence and the like.
There is a need, therefore, to provide a general purpose label and tape construction which is repulpable and wherein the adhesive employed is not sensitive to changes in relative humidity and where no special precautions are required for storage or use of a label or tape.